Why protect your lips from UV radiation?

Lips are among the face’s most sensitive areas, including to UV rays.

This vulnerability is due to their specific anatomical structure: unlike the skin elsewhere on the body, the lip mucosa lacks a thick stratum corneum and contains very few keratinocytes and melanocytes. Lips therefore contain almost no melanin, the protective pigment produced during sun exposure. This explains why lips do not tan, but it does not mean they are immune to sun damage. Moreover, the lip skin is nearly devoid of sebaceous glands, the organs that synthesize sebum. It is therefore almost unprotected by the hydrolipidic film, the water, sweat, and sebum layer that covers the rest of the body. That is why lips dry out and become more sensitive to external damage, including UV radiation.

Even though UV rays are not the only cause of lip cancers, they are a notable contributing factor. This is true for people who work outdoors, such as roofers, farmers, sailors, and horticulturists. Protecting the lips from sunlight is more than a comfort measure; it is a public health action that can prevent serious lesions.

Chronic exposure to ultraviolet radiation promotes the development of actinic cheilitis. This precancerous lesion, called actinic keratosis of the lip, results from abnormal keratinocyte proliferation after repeated sun exposure. Symptoms vary: dryness, scaling, erythema, atrophy, and ulceration. Over time, lesions may progress to invasive squamous cell carcinoma of the lip. This aggressive cancer has a poorer prognosis when diagnosis is delayed. Precancerous lip lesions are underrecognized due to lack of awareness.

Protecting your lips from sun exposure helps prevent cancerous lesions.

Several studies have shown the importance of photoprotection. Research conducted in Brazil with 404 adults demonstrated a 47.1% prevalence of actinic cheilitis in the population, especially among individuals exposed to sunlight for more than four hours per day. Among these participants, use of a physical barrier, such as a wide-brimmed hat, with or without sunscreen, was associated with a significant 33% reduction in the risk of actinic cheilitis. This study highlights the importance of lip sun protection, a neglected area. Despite this reality, another survey of 119 beach workers in Brazil found that only 7.5% used a lip balm with SPF and fewer than one third applied body protection. These figures indicate a lack of awareness of sun-related risks, particularly for the lips.

Several products are available to protect the lips from the sun. Most come as sun sticks, or lip balms enriched with SPF, but lip sunscreens are available. These products form a protective film against UV rays and their rich texture limits water evaporation from the lips. In addition, the advantage of sun sticks and lip balms resides in their portable format, easy to slip into a pocket or bag, which encourages application throughout the day. Sun protection must be reapplied regularly after meals.

Choosing a lip balm or sunscreen stick with an SPF of at least 30 preserves lip suppleness and reduces the risk of precancerous lesions such as actinic cheilitis.

• VARVAKI RADOS P. & al. Sun protection as a protective factor for actinic cheilitis: cross-sectional population-based study. Oral diseases (2022).

• DE CAMPOS L. & al. Prevalence of and risk factors for actinic cheilitis in Brazilian beach workers. Journal of Dental Health, Oral Disorders & Therapy (2022).

• HAFSI W. & al. Cheilitis. StatPearls (2023).

• DA SILVA MARCELINO P. & al. In vitro photoprotection and functional photostability of sunscreen lipsticks containing inorganic active compounds. Cosmetics (2023).